You may have heard about a brain-eating amoeba discovered in the South that is mongering fear into rafters, kayakers, and river-goers this summer. A single-cell organism called Naegleria fowleri has been responsible for the deaths of two paddlers in the past two months — one in Texas and one in Ohio (while the amoeba was contracted in North Carolina).

The amoeba causes a rare — but deadly — infection called primary amebic meningoencephalitis (PAM). The disease causes severe headaches, fever, nausea, and vomiting in those infected, before symptoms increase in severity. The final state of PAM causes seizures, hallucinations, coma, and death. The amoeba that causes PAM is believed to be contracted only through the nose — traveling up the olfactory nerves and attacking the brain.

In the past 54 years, only 138 cases of PAM have been reported in the U.S. Unfortunately, all but three cases were deadly. And while it is alarming to think that it’s possible to contract a “brain-eating” amoeba on your next paddle, chances are that you won’t. According to Outdoor Foundation, there are 23.9 million people in the U.S. who undertake paddling activities per annum. Taking into consideration that two rafters have died this year due to PAM, chances of falling victim to the disease after your next river raft is less than 0.000000092 percent.

However, that doesn’t mean that you shouldn’t be careful when it comes to waterborne illnesses. According to studies, 32 states in the U.S. reported 90 recreational water-associated outbreaks to Centers for Disease Control and Prevention’s (CDC) Waterborne Disease and Outbreak Surveillance System (WBDOSS) from 2011 to 2012. The report revealed that the 90 outbreaks were responsible for at least 1,788 reported cases of illness, 95 hospitalizations, and one death.

Waterborne illnesses are surprisingly common, if much less harmful. Giardia and Cryptosporidium are microscopic parasites or cysts that can be found in water, and during the past two decades, Giardia infection has become recognized as one of the most common causes of waterborne disease (found in both drinking and recreational water) in humans in North America. E. coli (more than 8,598 cases), dysentery (200,000 cases), and traveler’s diarrhea (10 million cases) account for a combined count of more than 10,208,000 ill adventurers per year.

In a study from Oregon State University, nearly 40 percent of surfers included in a test reported ear infections or discharge at some point during surfing; 30 percent, a sore throat or cough; 16 percent experienced diarrhea; 10 percent, fever; and 7 percent had vomited. Kayakers commonly get sick from contaminated rivers. In one study, Giardia was diagnosed in 14 percent of U.S. paddlers.

Heavy rains that flush pollution into the ocean and rivers are often to blame for recreational water contamination. Algae blooms in lakes often cause ear and sinus infections. Animal feces and runoff are also common causes for contamination. Here are a few ways to avoid contracting anything from water that may be contaminated: